htext(n) BLT Built-In Commands htext(n)______________________________________________________________________________NAME
htext - Create and manipulate hypertext widgets
SYNOPSIS
htext pathName ?option value?...
_________________________________________________________________DESCRIPTION
The htext command creates a new window (given by the pathName argument)
and makes it into a htext widget. Additional options, described above,
may be specified on the command line or in the option database to con‐
figure aspects of the widget such as its color and font. At the time
this command is invoked, there must not exist a window named pathName,
but pathName's parent must exist. The htext command returns its path‐
Name.
The htext widget is hybrid of a non-editable text widget and a geometry
manager (e.g. the packer). It displays text (optionally read from
file) in a window. Text can be scrolled either horizontally or verti‐
cally using the htext window as a viewport. In addition, Tcl commands
can be embedded into the text which are evaluated as the text is
parsed. Text between special double characters (percent signs "%%") is
immediately passed to the Tcl interpreter for evaluation.
Furthermore, any widget or widget hierarchy can be packed in-line and
made to appear on the current line of the text. Widgets are packed
using the htext append command. All widgets must be children of the
htext window and must already exist before packing. Once a widget has
been packed it cannot be moved to a different position within the text.
Widgets can be resized but they will remain at the same position within
the text.
Before a file or text string is parsed by the htext widget, all the
widget's current children are destroyed. You can reload files or text
without worrying about unmapping or destroying each child window
beforehand.
Setting the either the -filename or -text configuration option will
adjust the value of the other. If both options are set, the file takes
precedence. When a new file is read using the -filename option, the
value of the -text option is reset to the empty string. Likewise, when
the -text option is set, the string representing the -filename option
is cleared.
FILE FORMAT
The format of htext text file is typically ASCII text. Text enclosed
by special double characters (by default, percent signs '%%') is inter‐
preted and executed as Tcl commands. The special character may be
specified by the -specialchar option. In the following example of a
htext file, a button widget is appended to the text between the words
"a" and "which". The pathName of the htext widget is ".ht".
This will be displayed as normal text.
But this will become a %%
button .ht.button -text "button" -fg red
.ht append .ht.button
%% which can invoke a Tcl command.
INDICES
Some of the widget operations (selection, gotoline, search, etc.) take
one or more indices as arguments. An index is a string used to indi‐
cate a particular place within the text, such as the first and last
characters in a range to be selected.
An index must have one of the following forms:
line.char Indicates char'th character on line line. Both lines and
characters are number from 0, so "0.0" is the first begin‐
ning of the text. Char may be undesignated. In this case
a character position of 0 is assumed.
@x,y Indicates the character that covers the pixel whose x and y
coordinates within the text's window are x and y.
end Indicates the end of the text.
anchor Indicates the anchor point for the selection, which is set
with the selection operation.
sel.first Indicates the first character in the selection. It is an
error to use this form if the selection isn't in the entry
window.
sel.last Indicates the character just after the last one in the │
selection. It is an error to use this form if the selec‐
tion isn't in the entry window.
VARIABLES
The following global Tcl variables are maintained when an htext file is
parsed.
htext(widget)
is the pathname of the htext widget.
htext(file)
is the name of the file the htext widget is currently parsing.
It is the empty string when the -text option is used.
htext(line)
is the current line number in the text.
This information might be used to construct hyper links between differ‐
ent files and/or lines.
SYNTAX
The htext command creates a new Tcl command whose name is pathName.
This command may be used to invoke various operations on the widget.
It has the following general form: pathName oper ?args? Oper and args
determine the exact behavior of the command.
OPERATIONS
The following operations are available for htext widgets:
pathName append window ?option value?...
Embeds the widget window into the htext widget. Window is the
pathname of the widget to be embedded which must be a child of
pathName. Window will be positioned in the htext widget at the
current location of the text. If option and value pairs are
present, they configure various aspects how window appears in
pathName. The following options are available.
-anchor anchorPos
Specifies how window will be arranged if there is any
extra space in the cavity surrounding the window. For
example, if anchorPos is center then the window is cen‐
tered in the cavity; if anchorPos is w then the window
will be drawn such it touches the leftmost edge of the
cavity. The default is center.
-fill style
Specifies how the window should be stretched to occupy
the extra space in the cavity surrounding it (if any
exists). Style is none, x, y, both. If style is x, the
width of window is expanded to fill the cavity. If style
is y, the height is expanded. The default is none.
-height pixels
Sets the height of the cavity surrounding window. If
pixels is zero, the height of the cavity will be the same
as the requested height of window. If pixels is less
than the requested height of window, window will be
reduced to fit the cavity. The default is 0.
-ipadx pad
Sets the amount of internal padding to be added to the
width window. Pad can be a list of one or two numbers.
If pad has two elements, the left side of window is
extended by the first value and the right side by the
second value. If pad is just one value, both the left
and right sides are padded by evenly by the value. The
default is 0.
-ipady pad
Sets an amount of internal padding to be added to the
height of window. Pad can be a list of one or two num‐
bers. If pad has two elements, the top of window is
padded by the first value and the bottom by the second
value. If pad is just one number, both the top and bot‐
tom are padded evenly by the value. The default is 0.
-justify justify
Justifies window vertically within the cavity containing
it in relation to the line of text. Justify is top, bot‐
tom, or center. If justify is center the widget is cen‐
tered along the baseline of the line of text. The
default is center.
-padx pad
Sets the padding on the left and right sides of window.
Pad can be a list of one or two numbers. If pad has two
elements, the left side of window is padded by the first
value and the right side by the second value. If pad has
just one value, both the left and right sides are padded
evenly by the value. The default is 0.
-pady pad
Sets the padding above and below window. Pad can be a
list of one or two numbers. If pad has two elements, the
area above window is padded by the first value and the
area below by the second value. If pad is just one num‐
ber, both the top and bottom are padded by the value.
The default is 0.
-relheight value
Specifies the height of the cavity containing window rel‐
ative to the height of pathName. Value is real number
indicating the ratio of the height of the cavity to the
height of pathName. As the height of pathName changes,
so will the height of window. If value is 0.0 or less,
the height of the cavity is the requested height window.
The default is 0.0.
-relwidth value
Specifies the width of the cavity containing window rela‐
tive to the width of pathName. Value is real number
indicating the ratio of the width of the cavity to the
width of IpathName. As the height of pathName changes,
so will the height of window. If value is 0.0 or less,
the width of the cavity is the requested width of window.
The default is 0.0.
-width value
Species the width of the cavity containing the child win‐
dow. Value must be in a form accepted by Tk_GetPixels.
If value is greater than zero, the cavity is resized to
that width. If the requested window width is greater
than the cavity's width, the window will be reduced to
fit the cavity. By default, the cavity is requested
width of the child window.
pathName configure ?window? ?option? ?value option value ...?
Queries or modifies the configuration options of the text widget
or one of its embedded widgets. If no window argument is
present, the htext widget itself is configured. Otherwise win‐
dow is the pathname of a widget already embedded into the htext
widget. Then this command configure the options for the embed‐
ded widget.
If option isn't specified, a list describing all of the current options
for pathName or window is returned. If option is specified, but not
value, then a list describing the option option is returned. If one or
more option and value pairs are specified, then for each pair, the
htext or embedded window option option is set to value.
The following options are valid for the htext widget.
-background color
Sets the background of the htext widget to color. This
default is white.
-cursor cursor
Specifies the cursor for the htext widget. The default
cursor is pencil.
-filename fileName
Specifies a htext file to be displayed in the window. If
the value is the empty string, the -text option is used
instead. See the section FILE FORMAT for a description
of the htext file format.
-font fontName
Sets the font of the text in the htext widget to font‐
Name. The default is *-Helvetica-Bold-R-Nor‐
mal-*-12-120-*.
-foreground color
Sets the foreground of the htext widget to color. This
is the color of the text. This default is black.
-height pixels
Specifies the height of the htext widget window.
-linespacing pixels
Specifies the spacing between each line of text. The
value must be in a form accepted by Tk_GetPixels. The
default value is 1 pixel.
-specialchar number
Specifies the ASCII value of the special double character
delimiters. In htext files, the text between these spe‐
cial characters is evaluated as a block of Tcl commands.
The default special character is the 0x25 (percent
sign).
-text text
Specifies the text to be displayed in the htext widget.
Text can be any valid string of characters. See FILE FOR‐
MAT for a description.
-xscrollcommand string
Specifies the prefix for a command used to communicate
with horizontal scrollbars. When the view in the htext
widget's window changes (or whenever anything else occurs
that could change the display in a scrollbar, such as a
change in the total size of the widget's contents), the
widget invoke string concatenated by two numbers. Each
of the numbers is a fraction between 0 and 1, which indi‐
cates a position in the document. If this option is not
specified, then no command will be executed.
-yscrollcommand string
Specifies the prefix for a command used to communicate
with vertical scrollbars. When the view in the htext
widget's window changes (or whenever anything else occurs
that could change the display in a scrollbar, such as a
change in the total size of the widget's contents), the
widget invoke string concatenated by two numbers. Each
of the numbers is a fraction between 0 and 1, which indi‐
cates a position in the document. If this option is not
specified, then no command will be executed.
-width pixels
Specifies the desired width of the viewport window. If
the pixels is less than one, the window will grow to
accommodate the widest line of text.
-xscrollunits pixels
Specifies the horizontal scrolling distance. The default
is 10 pixels.
-yscrollunits pixels
Specifies the vertical scrolling distance. The default is
10 pixels.
pathName gotoline ?index?
Sets the top line of the text to index. Index must be a valid
text index (the character offset is ignored). If an index isn't
provided, the current line number is returned.
pathName scan mark position
Records position and the current view in the text window; used
in conjunction with later scan dragto commands. Position must
be in the form "@x,y, where x and y are window coordinates.
Typically this command is associated with a mouse button press
in the widget. It returns an empty string.
pathName scan dragto position
Computes the difference between position and the position regis‐
tered in the last scan mark command for the widget. The view is
then adjusted up or down by 10 times the difference in coordi‐
nates. This command is can be associated with mouse motion
events to produce the effect of dragging the text at high speed
through the window. Position must be in the form "@x,y, where x
and y are window coordinates. The command returns an empty
string.
pathName search pattern ?from? ?to?
Returns the number of the next line matching pattern. Pattern
is a string which obeys the matching rules of Tcl_StringMatch.
From and to are text line numbers (inclusive) which bound the
search. If no match for pattern can be found, -1 is returned.
pathName xview ?position?
Moves the viewport horizontally to the new text x-coordinate
position. Position is the offset from the left side of the text
to the current position and must be in a form accepted by
Tk_GetPixels. If position is not present, the current text posi‐
tion is returned.
pathName yview ?position?
Moves the viewport vertically to the new text y-coordinate posi‐
tion. Position is the offset from the top of the text to the
current position and must be in a form accepted by Tk_GetPixels.
If position is not present, the current text position is
returned.
BUGS
Text with embedded tabs can be obscured by child windows when scrolled
horizontally.
KEYWORDS
hypertext, widget
BLT 2.4 htext(n)
